Call-distributing arrangement for telephone plants



G/A. BETULANDER AND M. G. PALMGREN. CALL DISTRIBUTING ARRANGEMENT FOR TELEPHONE PLANTS.

APPLICATION FILED NQV. 23, I920.'

Patented Apr. 19, 1921.

3 SHEETS-SHEET I.

ETULANDER AND N. G. PALMGREN. CALL DISTRIBUTING G. A.B

ARRANGEMENT FOR TELEPHONE PLANTS. APPLICATION FILED NOV. 23.1920,

Patented Apr. 1-9, 1921.

3 SHEETS-SHEET 2.

G. A. BETULANDER AND N. G. PALMGREN.

CALL DISTRIBUTING ARRANGEMENT FOR TELEPHONE PLANTS. APPLICATION FILED NOV. 23, 1920.

1,375,351 I v Patented Apri 19, 1921..

3 $HEETSSHEET 3.

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CALL-DISTRIBUTING GEMENT FOB TELEPHONiE- ZLANTS.

Specification of Letters Patent.

rac mes Apr. as, rear.

Application'filed November 28 1920. Serial No. 426,044.

To all whom it may concern:

Be it known that we, GOTTHILF ANSGARIUS BETULANDER and Nuts GUNNAR PALMGREN, subjects of the King of Sweden, and resid-. ing at, respectively, Sodertorns Villastad, Sweden, and Varvsgatan 14, Stockholm, Sweden, have invented a new and useful Improvement in Gall-Distributing Arrangements for Telephone Plants, of which the following is a specification.

The invention relates to terns, particularly automatic or semirautomatic systems, in which .the subscribers lines or the junction lines over which the talking connections are established are divided into groups which are served by switching devices common to all the lines in each group. In such systems means must generally be provided for insuring that the difl'erent calls shall be successively dealt with even when several calls simultaneously reach the swltchlng device in question, forv the purpose of preventing double connections or disturbances in the connecting operations. The diilerent lines are then provided with relays or like switching devices which, during the switching operation, mark the line to be connected in a particular way,

so that only this line obtains connection with the line in uestion or the common switching device. Vhen two or more calls occur simultaneously there must be means for preventing more than one of said markingrelays being brought into operation or remaining in the operated position. Systems are known in which this is attained by said relays mutually controlling their C11- cuits so that, on operating, they mutually disconnect each other, only one of the relays being thus capable of keeping its armature attracted. In suchan arrangement, however, the circuits of the different marking relays will include on an average a relatively large number of contacts connected in series, and this number increases with the number of lines and marking relays whereby the reliability ofthe service is diminishcd. The object of the present invention is to provide a call distributer arrangement which insures the, successive connection of simultaneously calling lines and which is simpler and more reliable than the known arrangement above mentioned. The invention chiefly consists in that the lines and telephone systhe appertaining marhng relays are divided into a plurality of groups, the marking relays which control the circuits of one another group-wise by the. difierent relay groups, being provided with group marking relays which are brought into operation when a call occurs in the appertaining group and which control the circuits'for the diii'erent groups of individual mar ing relays in such a manner that when calls occur simultaneously in different groups only one marking relay in one of sald groups can operate or be kept in its operated position. The arrangement is preferably such that the common circuit of each group of marking relays is carried. overback contacts in series of the group relays of all those groups which are connected to the source of current at points between the group in question and the source of current. By such a mutual group control of the circuits of the marking relays a considerable reduction of the number of contacts in said circuits and a corresponding simplification of the circuits primary groups, are provided with secondary group relays so arranged as to be brought into operation, when a call occurs in the appertaining secondary group, said secondary group relays controlling-the circuits of the different secondary relay groups in'a similar way as the primary group relays control the circuits of the primary relay groups. In this way the circuits are further simplifiedan'd the number of contacts is further reduced.

1 The invention is illustrated by the accompanying drawings, in which Figures 1, 2 and 3, show schematically three different forms of the invention.

In the circuit arrangement shown in Fig.

vention in such a way that only one out of a plurality of simultaneously calling lines can be marked as calling. The lines and the marking relay MR a ertaining relays are arran ed in oups Gi G G and the groups 1 and 2 are provided with group out offrelays GR and IR res ectively. Thev dilierent' marking relays v nected at one side to on pole jparth) of the battery B over back contacts" K, of the marking relays, and at the other side to the otheikpole of the batteryover back '00 tacts K of the group relays, the arrangement being such that the circuit of each marking'relay is carried over back contacts connected in series of all marking relays of the same group connected between this relay and the pole in question of the battery, Whereas the common circuit for the marking relays in each group is carried over back contacts of the group relays of all relay groups connected. between this relay group and the opposite pole of the battery.

Upon a call occurrin for instance on the third line of the group 2 the corresponding line relay LR is energized whereby a circuit 1 is completed through the corresponding The latter energizes and closes a circuit 2 'through the group relay GR which then operates yet without any other effect than that the relay group G is cut oil. If two or more calls occur simultaneously in the same group only that marking relay MR which is next to the earthconnected pole of the battery will evidently remain in operated position, as this relaycuts off the marking relays located to the right of the sameyat its contact K or K respective] If LR and LR are thus operated simultaneously, only MR remains operated and only the appertaining line is marked. After completed connection of this line the appertaining relay LR is deenergized, whereby MR is caused to deenergize and to complete the circuit 1' of MR which now efiects the connection of the appertaining line. In case calls should occur simultaneously in two different groups, for instance on the third lines-0f the grou s Gr and G partly said circuit 1 and part y a circuit 3 are closed whereby both relays MR are energized simultaneously closing partly the circuit 2 throu h GR and partly a circuit 4 through G Thev relay GR then opens the circuit of'the in each group G are jointly conlatter. Should calls occur simultaneouslycalls may enter immediately after 'c)ne another so as to cansedisturbance in the connecting operation started by the first call. This drawback is eliminated in the arrangement shown in Fig. 2 byeach call causing a disconnection of all marking relays except that one belonging to the calling line, which relay connects itself into a holding circuit.

Fig. 2 shows the invention as applied to the pre-selecting section of an automatic or semi-automatic telephone exchange. L to L are subscribers lines enterin the preselecting section and FL to F 3 are the junction lines extending from this switching section, the connection with the latter being efiected automatically on removing the telephone by means of a testingdevice S which is common to a group of, for instance,

subscribers lines and which on being engaged line, said connecting relay connecting the calling line to this junction line. In the example shown inthe drawing the connection is efi'ected by means of a switchin device in which said connecting relays A and the marking relays MR allotted to the subscribers lines form operating and selecting electromagnets respectively and in which the connection is effected y energizing partly the selecting magnet (the relay MR) corresponding to the subscribers line and partly the operating magnet (the relay AR) corresponding to the junction line inquestion,-the selecting magnet HL efl'ecting such a mechanical marking of the series of contact sets KG corresponding to the subscribers line that should the operating magnet AR operate owing to another call, only the contact set capable of establishing the desired connection is operated.

LR and UR are the ordinary line and cut oil relays.

The subscribers lines and the appertaining relays are divided into groups of, for instance, 10 lines.

The drawing shows complete circuits for only one such ro p with the appertaining group relay Glt. The mutual connection of these groups appears" from the connection represented by dotted lines and comprising the group relays GR and GR for two other and through a relay IR. he marking relay MR energizes and connects itself into a holding circuit 7 containing the group relay GR and extending over back contacts of all group relays connected between this group relay and the battery B. GR? cuts in all testing relays PR to the corresponding test wires, those testing relays which correspond to disengaged junction lines then re-v ceiving a current impulse. The testing relay; however, which is next to the battery opens the under test circuits as is seen from the drawing, only the test circuit corresponding to this relay, for instance, the circuit 8, remaining closed. This circuit contains' an operating winding AL of the relay AR" and this relay therefore energizes connecting itself into a circuit 9 and establishing connection between the subscribers line and the junction-line in question over the contact set K G A circuit 10 is then closed through the cut ofi' relay UB and the holding winding HL of the relay AR over the third wires C anl C The relay UB opens the circuit 5 of the line LE which in turn opens the circuit 7 of the marking relay MR and the group relay GR whereby the testing device S is disconnected and the switching operation finished.

If calls should occur simultaneously in two difierent groups, for instance, the third and the second groups, the corresponding marking relays energize simultaneously and thegroup relays G11 and GR receive a current impulse simultaneously. The relay GR then, however, opens the holding cir cuit of the marking relay in the first group and at the same time also the operating circuit of this relay so that the latter after having been de'e'nergized cannot again energize. Thus, only the marking relay of the calling line in the second group remains operated. A call occurringimmediately after another call and! when the operation for connecting the first calling line is going on :"cannot therefore operate the appertaining marking relay until after the connection ofthe said line has been completed as the operating circuits or" all marking relays are disconnected at the group relay in question as long as the connecting operation is going on.

In this arrangement other means are provided for preventing a simultaneous markin of more than one call if two or more ca ls should occur simultaneously. in the same group. In such a case the marking relays will at first energize, however, 'asthese relays then receive only half the current or even still less of the current passing through the group relay and the relay IR, they cannot keep theirarmatures attracted but release them. As, however, the self-induction and therefore the time in which a relay releases its armature is never exactly the same for two relays, one of the relays will release its armature before the other, its corresponding operating circuit being then again closed, so that the relay again energizes before the operating circuit of' the other relay is yet closed. The'c'orresponding group relay then opens the operating circuit and the relay last mentioned can therefore no longer be operated until the connection of the first marked line has been completed.

Flg. 3 shows a still more simplified circuit arrangement in a representation similar to the arrangement according to Fig. .1.

The arrangement for preventing a simulta-- neous marking of calls in different roups and for preventing disturbances by ca ls following immediately after one another is the same as in Fig. 2. For preventing a simultaneous marking of several calls in the same group, however, the following means are provided :The difi'erent groups G G G have an equal number of lines and marking relays and the relays in the different groups which correspond to each other are ut together in groups SG SG SG W ich as distinguished from the first mentioned rimary groups will be called secon ar groups. These groups are provided with secondary group relays SGR SGR SGR which correspond to the primary group relays, inasmuch as they control the operating circuits for the marking relays, so that the simultaneous marking of a plurality of calls in different secondary groups, 71. e. in the same primary groups, is prevented. For this purpose all marking relays of each secondary group are jointly connected to the positive pole (earth) of the battery over series connected back contacts K, K, K, of the group relays of all secondary groups connected between the group in question and said pole of the battery. The secondary group relays are-preferably included in the circuit common to all marking relays in the corresponding secondaryv grou If two or more calls occur simultaneously in the same primary group, 2'. e. in different secondary groups, it is evident that only one of the secondary group relays can remain in its operated position and consequently only the corresponding line is marked as calling. When calls occur simultaneously in several primary groups, the switching operation controlled by{ the primary group relays G13 GR G manner as in the arrangement according to connection of simultaneously calling telephone lines, the combination of anumber of lines, a number of relays adapted to mark corresponding lines as calling, the lines and relays being divided into a plurality of groups, a group relay allotted to each group and adapted to operate upon a call occurring in its group and means adapted upon such group relay operating to prevent more than one of the marking relays from. remaining operated.

2. In means for effecting the successive connection of simultaneously calling telephone lines, the combination of a number of lines, a number of relays adapted to mark corresponding lines as calling, the lines and relays being divided into a plurality of groups, a group relay allotted to each group and adapted to operate upon a call occurring in its group, a source of current adapted to energize the relays, and a circuit for each group of marking relays carried over series connected back contacts of thegroup relays of the groups connected be-.

tween its own group and the source of current.

3. In means for eflecti'ng the successive connection of simultaneously calling telephone lines, the combination of a number of lines, a number of relays adapted to mark corresponding lines as calling, the lines'and relays being divided "into a plurality of groups, a group. relay allotted to each group and adapted to operate upon a call'occurring in its group, the marking relays which correspond to each other in the difi'erent groups being divided into secondary groups, a secondary group relay allotted to each secondary group and adapted to operate upon a call occurring in its secondary group,

and a source of current, the marking relays of each secondary group being jointly connected to the source of current over'series connected contacts of the secondary group relays of all relay groups connected between the secondary group in question and the source of current.

4a. In means for efiecting the successive connection of simultaneously calling .telephonelines, the combination of a number of lines, a number of relays adapted to mark corresponding lines as calling, the lines and relays being divided into a plurality of groups, a group relay allotted to each group and adapted to operate upon .a call 0c-' in the samecurring in its group, the marking relays which correspond to each other in the diflerent groups being divided into secondary groups, a secondary group relay allotted to each secondary group and adapted to operate upon. a call occurring in its secondary group, and a source of current, the marking relays being connected in each secondary lays being divided into a plurality of groups,

a group relay allotted to each group and adapted to operate upon a call occurring in its group, the marking relays which correspond to each other in the diiterent groups being. divided into secondary groups, a secondary group relay allotted to each secondary group and adapted to operate upon a call occurring in its secondary group, and a source of current, the'marking relays being connected in each secondary group to one pole of the source -'of current over contacts ofthe secondary group relays and in each primary. group to the opposite pole of the source of current over contacts of the primary group relays, the secondary group re- .lays being included in the circuit common to lines, a number of relays adapted to mark corresponding lines as calling, the lines and relays being divided into a plurality of groups, and a grouprelay allotted to each group and adapted to operate upon a call occurring in its group, each group relay being adapted upon energizing to put all marking relays except that one belonging to the calling line in question, which remains energized, out of operation.

7. In meansfor effecting the successive connection of simultaneously calling telephone lines, the combination of anumber of lines, a number of relays adapted to mark corresponding lines as calling, the lines and relays being divided into a plurality of groups, agroup relay allotted to each group and adapted to operate upon a call occurring in its group, a source of current and a holding circuit common to all the marking relays of each group and carried over series connected back contacts of the group relays of all relay groups connected between the group in question and the source of current. each marking relay being adapted upon energizing to connect itself into the holding.

circuit of its group.

8. In means for effecting the successive connection of simultaneously calling telephone lines, the combination of a number of lines, a number of relays adapted to mark corresponding lines as calling, the lines and relays being divided into a plurality of groups, a group relay allotted to each group and adapted to operate upon a call occurring in its group, a source of current and a holding circuit common to all themarking relays of each group and carried over series connected back contacts of the group relays of all relay groups connected between the group in question and the source of current, each marking relay being adapted upon energizing to connect itself into the holding circuit of its group, the group relays being included in the corresponding holding circuits.

In testimony that We claim the foregoing as our invention We have signed our names this 28th day of October, 1920.

' GOTTHILF ANSGARIUS BETULANDER.

WlLS GUNNAR PALPIIGREN' 

